True Trac vs Open Diff

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Viking with a Hammer

Having owned an Econoline 350 (whale tail version), the Truetrac is the only viable option for a rear diff for that 2wd van. Unless extensively modified, Econolines aren't as forgiving as the trucks are.

A Detroit locker would be perfect if you never, ever, see snow and have tires that are excellent in the rain. But IME, rear lockers oftne make thing worse in 2wd.

Observer

WSS, he drives a 2WD Van. With driveability problems of full lockers, i'd still put money on a True Trac. Another reason is cost. True Trac is at most half the price of an ARB. No compressor, tubing, switches, complicated install, or electrical circuits. I had woes with my front and rear ARB's on my rock crawler. Thick dust, like in the desert was a switch killer. BTDT. Passing weeds, rocks or floatsam would wreak havoc with the air tubing. jefe

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Adventurer

FWIW the owner of a very reputable diff shop here advised me NOT to go with the Detroit True Trac any longer.
He said it isn't made to the same standards as just a couple years ago, lesser quality materials, tolerances and QC. I "think" he mentioned it being made offshore now also but not sure.
I have a buddy who has abused his dual True Trac'd Scout for a couple decades and they have been great for what they are (he wheels with us dual locked guys all the time and does pretty darn well) and I have one in my Mustang but the newer version he recommends against.

Adventurer

Last year, I had a True Trac installed in my 69 Fairlane Cobra with a torque monster 428CJ engine. It has held up flawlessly so far. I don't drive it all the time but when I do, it gets abused often. Your shop owner may be right but you couldn't prove it by me. When I gave the True Trac to the shop to install it, it looked like a very good quality part. I consider that shop a very reputable shop and they had only good things to say about True Trac.

Explorer

How well behaved are TruTrac rear ends on the highway in snow or rain? I still have bad memories of the first time I drove my 82 Mustang GT with factory clutch type Traction Lok on the interstate in the snow going up a grade. Suddenly the back end could not make up it's mind which lane it wanted. Only solution push in the clutch.

Adventurer

How well behaved are TruTrac rear ends on the highway in snow or rain? I still have bad memories of the first time I drove my 82 Mustang GT with factory clutch type Traction Lok on the interstate in the snow going up a grade. Suddenly the back end could not make up it's mind which lane it wanted. Only solution push in the clutch.

They act the same. One tire spins and the other tire starts to get torque.
My mustang does the same thing but it's still much better than an open diff. After driving Detroit Locker and limited slip vehicles exclisuvely for the last 34 years it's not a big deal.

Adventurer

I have to agree with Scout. The True Trac operates smoothly without notice. Auto lockers engage the outside wheel around corners by basically an on and off method. I have an auto locker on one of the differentials on my SCCA road racing sports car and it can be a handful in the corners when the track is wet. It can also be kind of jerky when lightly accelerating around sharp corners when not up to speed on a dry track. The differentials for my race car that work more like a True Trac are much more predictable in the corners as long as I don't put too much power to it and break both tires loose.
The best thing about an auto locker is they rotate both wheels at the same speed under power when going straight no matter how much traction is available. This is very useful off-road (especially if one tire is not touching the ground). They also keep both wheels turning in corners regardless of traction available.

Apprentice Geezer

As soon as Eaton bought Detroit Locker I feared degradation in quality (it happens whenever you get bean counters trying to maximize profit).
Be aware that Tru-Trac is a (Eaton) brand name and other companies make helical geared (Torsen style) "limited" slip differentials.
Also Ford uses/used a "traction lock" clutch style limited slip in many vehicles; Torsen style limited slips seem to be relatively hard to find in scrap yards (at least for Dana axles, Jeep products and Ford 8.8 axles).
I got mine for the D35 IFS in the explorer from;https://torsen.com/
I will never again use a Detroit Locker on or off road (it tried to kill me too many times on ice).
I also have broken several gov-loks in difficult terrain (some chance of body damage) with 35" tires (not huge).
Tried (because they came in the used vehicles or junk yard substitution axles) many brands/types of OEM limited slips ; none worked particularly well in a dual purpose on/off road daily driver/semi extreme 4 wheeler (tins Torsen is potentially an exception).

For me its ARB (selectable air lockers) or Torsen (limited slips); so far no problems with either... (your experiences may vary).